Heterocyclic color couplers



Patented Apr. 8, 1947 HETEROCYCLIC COLOR COUPLERS V Abraham Bavley, Binghamton, N. Y., assignor to General Aniline & Film Corporation; New York, N. Y., a corporation of Delaware No Drawing. Application Jan e 7,1944," Serial No. 539,177

The present invention relates to color photosraphy and is particularly concerned with photographic color forming or color couplin components which are adapted to be incorporated in photosensitive emulsion layers in the production of photographic film, papers and the like.

This invention is an improvement in the process of colorforming development which was first described in United States Patents No. 1,055,155 and No. 1,102,028 to Fischer, in accordance with which colored photographic images are produced by means of a coupling reaction between the oxidation product of a photographic developer containing free amino groups, for instance, phenolic diamines, especially the monoor unsymmetrically disubstituted ones, like p-dimethylaminoaniline or methoxy-p-dimethylaminoaniline and the like, and an intermediate or coupling component. As is well known, this coupling occurs at those points Where a silver image is produced by reduction of the silver halide by the color developer with resulting formation, at these points, ofthe oxidation product of the developer, which couples with the intermediate or coupling component. The coupling component can be present in the photographic developer. However, in accordance with the preferred methods-for practicing this color forming development process, non-di'fiusibl color forming or coupling components are employed which are incorporated in the photosensitive emulsion during manufacture. It is particularly desirable that such non-diffusible color forming or coupling components be employed in case severaldifierently sensitized photosensitive emulsion layersare coated on a single support as is the case in three-color photographic processes in which the so-called integral tripack films are employed, since, in such cases, any wan dering or diffusing of the color component from the layer in which it is incorporated would cause inaccurate color rendition, while attempts to employ the color coupling component in the color forming developer, in such cases, unnecessarily complicates the process of developing.

The present invention is particularly concerned with a novel type of color component having an 6 Claims.

2 nents since the methyl group is relatively active and coupling with the color forming developer can occur-through this methlyl group. The activity of the methyl group, however, is insufii'cient for compounds of this type to be entirely satisfactory ascolor components for use in color photographic processes of the type'described above and, in general, compounds of this type are relatively weak color formers.

It is an object of this invention to produce compounds related to those heretofore proposed but which are so modified as to increase the activity."

of the active groups therein. Other and-further objects will be apparent as the present description progresses.-

I have discovered that if the active group-of- ,a color forming component is a part of a ring structure, the activity of the reactive groupissubstantially increased'and, on color forming development, greater coupling speed and more' ener -q getic coupling takes place. Therefore, in ,prac; ticing my invention,.I employ, .in' place of color forming components of the type Whichhave here tofore been employed and in which the starred methylene group is the active. group, relatedcornwhich may be represented by the following generic formula:

In the above formulas, Z represents the necessary atoms to make upa five or six membered N-hetero ring, which may be further substituted, n is 2, 3 or 4, and X represents halogen. It will be noted thatincompounds of this type, the reactive methylene group. or groups, which are starred, form a part of a ring.

Compounds of this type may readily be pre- Thus, ortho-substituted N-hetero 'cor'npo'u-iids,

such as pyridine, quinoline, benz'thiazole, beriaox azole, and the like, in which the carbon atom; adjacent to the heterogenous nitrogen atom, is-

substituted by an alkyl halide group, having 2 to .4 carbon atoms in the chain, may readily be quaternized by conventional Procedure, for instance,

' reaction proceeds in accordance with the follow- 1 dong. in which n is 1, 2 or 3 and Z stands for the necessary atoms to make up a five or six-memberedring which may be further substituted, These cyclic-substituted N-hetero compounds contain reactive methylene groups having a substantially enhanced activity since they form a part of a ring and coupling readily takes place through such reactive methylene groups with the usual color forming developers. The compounds may be readily incorporated in a photographic emulsion by any usual procedure, for instance, by dissolving a minor amount of the same in alkaline aqueous alcohol and incorporating such solution in a conventional gelatin photographic emulsion.

This invention-will be readily understood by reference to the following specific examples, which illustrate typical compounds embraced in this invention; Numerous other compounds containing the essential features of the present invention will suggest themselves to those skilled in the art.

' Example 1 3 POI:

carom-onion i beat CH: on of V H:

The thus obtained quaternized compound was then incorporated in a photographic emulsion .by

dissolving asmall amount thereof, generally about 8 grams, in 3 cc. of sodium hydroxide of 40% strength, 25 cc. of methanol andlO cc. of water and'was then added to 500 cc. of a gelatin emulsion of strength. When so incorporated in a photographic emulsion, the compound exerted no adverse effect on the emulsion. The emulsion was then coated on a glass plate in the usual manner for producing photographic plates and the plate exposed, On. development with a color forming developer, for instance, p-diethylaminoaniline, a yellow picture was obtained.

Example 2 Hydroxyethylbenzthiazole was treated with phosphorous trichloride in order to obtain chlorethylbenzthiazole. This was then dissolved in nitrobenzene and heated to a temperature slightly above its melting point but below the boiling point of nitrobenzene, a temperature of 120-180" 0. being satisfactory. The nitrogen atom of the thiazole group was quickly quaternized and the quaternary compound so formed precipitated from the nitrobenzene and was removed and washed. This reaction proceeded according to the following equation:

o-onionion C-CHaCHaG-l emulsion then coated on a glass plate and dried. The plate was then exposed and the image developed by a reversal process, a color forming developer, p-diethylaminoaniline, being employed in the second developing batch. A magenta picture was thus obtained.

I claim:

1. A photographic silver halide emulsion havt ing incorporated therein, as a color forming development component, a compound having the following formula:

wherein Z represents the necessary atoms to make 2. A photographic silver halide emulsion hav-' ing incorporated therein a color forming development component having the following formula:

wherein X represents halogen and n is a Whole number of from 2 to 4.

3. A photographic silver halide emulsion hav- 6 ing incorporated therein a color forming develop- 6. A photographic silver halide emulsion havment component having thefollowing formula: ing incorporated therein, as a color former, a

compound having the following formula:

s 5 \N/ A /C(FH2 I x crmm' \N CH3 wherein X represents halogen and n is a whole x number of from 2 to 4.

4. A photographic silver halide emulsion hav- Wherem X rep e nts en. ing incorporated therein, as a color former, a compound having the following formula: ABRAHAM BAVLEY- REFERENCES CITED CH= The following references are of record in the I file of this patent: X CHr-CH: wherein X represents halogen. UNITED STATES PATENTS 5. A photographic silver halide emulsion having incorporated therein, as a color former, a gg s i g t 1 J g 40 compound having the following formula: 6 ml ere FOREIGN PATENTS 1 Number Country Date Np 478,986 British Jan. 24, 1938 X I 504,376 British Apr. 24, 1939 536,673 British May 22, 1941 wherein X represents halogen. 

